For display systems, high pressure lamps represent the brightest and the most energy-efficient light sources. High pressure lamps are characterized by a broad spectrum, which includes substantial intensity in the yellow light wavelength. It is desirable, therefore, to incorporate the yellow light into display systems that use high pressure lamps.
To produce color, typical display systems employ three filters for red, blue, and green as primary colors. Incorporating yellow in such systems (for example, using a green/yellow filter), however, results in significant reduction of the color gamut of the system.
One solution to the above problem, in single-panel systems, incorporates yellow as a fourth primary color. While the color gamut is not reduced, a problem arises in a sub-optimized overall brightness of the display. This is due to the fact that when more primary colors are added, the (liquid crystal) panel may not have sufficient time to switch to a fully-on state for certain of the primary colors.
Two-panel systems provide enhanced brightness compared to single-panel systems, by dedicating a second panel to receive more color components of the emitted light. However, typical two-panel systems are not optimized; they continue to filter out the yellow light to ensure a good color gamut, and, as a result, limit the overall lumen output.
What is needed therefore are methods and systems for single-panel and two-panel color display systems that provide improved overall brightness and color gamut.